Pycnodysostosis is an inherited autosomal recessive disorder characterized by dysplasia of the skeletal system. It occurs in any human races with no disparity in gender or age predilection. The disease is diagnosed at a young age owing to the frequent fragile bone fractures. Craniofacial and dental manifestations may overlap with those of other craniofacial dysostosis; therefore, precise knowledge is essential in differential diagnosis as it may affect the treatment outcome. Here, we report three cases with typical clinical and radiological features, among which one presented with osteomyelitis of the mandible.

UNASSIGNED: Pyknodysostosis is a rare genetic disorder characterized by skeletal and craniofacial abnormalities. It is an autosomal recessive disorder caused by mutations in the gene encoding cathepsin K. Pyknodysostosis is associated with short stature, brittle bones, and distinctive facial features.
METHODS: This case report presents the clinical manifestations, diagnostic challenges, and management strategies of an 8-year-old male with pyknodysostosis, an extremely rare genetic disorder characterized by skeletal and craniofacial abnormalities. The patient\'s clinical presentation, radiographic findings, genetic testing results, and treatment approach are discussed. Additionally, the importance of genetic counseling and multidisciplinary care in managing this condition is emphasized.
UNASSIGNED: A multidisciplinary approach involving orthopedics, genetics, dentistry, and psychological support is crucial for managing patients with pyknodysostosis. Regular follow-up visits, careful monitoring of fractures, and appropriate interventions can improve the patient\'s quality of life and reduce complications.
CONCLUSIONS: The importance of early recognition, genetic testing, and multidisciplinary care is emphasized for effective treatment and support. Further research is needed to enhance our understanding of this rare genetic disorder and develop targeted therapies.

UNASSIGNED: A 9-month-old entire male domestic longhair cat presented with a history of pathological fractures, chronic musculoskeletal pain and poor growth. Multiple facial and skeletal abnormalities were identified on physical examination and advanced imaging (CT and radiographs). A variant in CTSK was identified in the affected cat following whole-exome sequencing (WES). The cat was managed symptomatically with diet, environmental modifications and analgesia.
UNASSIGNED: This is the first report of a cat with a similar clinical presentation and genetic variant to the hereditary human genetic disorder pyknodysostosis. In this case, WES was performed, which often facilitates the diagnosis of various hereditary disorders (ie, a conceptual framework for practicing feline genomic medicine). Despite the severe skeletal and appendicular abnormalities described, the cat was alive more than 2 years after its initial presentation.

UNASSIGNED: Pyknodysostosis is an uncommon inherited disorder associated with consanguinity, often presenting with sclerotic bone disease, short stature, dysmorphic features, and recurrent fragility fractures at an early age.
UNASSIGNED: A 34-year-old woman was evaluated for the cause of recurrent fragility fractures. She was born of a third-degree consanguineous marriage and had a twin brother who was of short stature. The index patient had a height of 141 cm, dysmorphic features including frontoparietal bossing, blue sclera with short stubby fingers and toes. Radiological evaluation revealed diffuse osteosclerosis with acro-osteolysis exclusively in the toes, apart from mid-facial hypoplasia, lack of pneumatization of the paranasal sinuses, dental abnormalities, and scoliosis. Dual-energy x-ray absorptiometry revealed increased bone mineral density. Based on the clinical features, the patient was tested for cathepsin K gene variants using next-generation sequencing and was found to be positive for a novel homozygous c.224T>C, p.Met75Thr likely pathogenic missense variant.
UNASSIGNED: This patient presented at a later age than expected with recurrent fragility fractures and the diagnosis was not suspected till adulthood, owing to the subtle clinical features. Confirmation with genetic testing helped in establishing the diagnosis.
UNASSIGNED: Pyknodysostosis, although uncommon, is one of the differential diagnoses for diffuse osteosclerosis presenting with recurrent fragility fractures. Next-generation sequencing in an appropriate setting may confirm the diagnosis.

Bone sclerosis is a focal, multifocal, or diffuse increase in the density of the bone matrix on radiographs or computed tomography (CT) imaging. This radiological finding can be caused by a broad spectrum of diseases, such as congenital and developmental disorders, depositional disorders, and metabolic diseases. The differential diagnosis can be effectively narrowed by an astute radiologist in the light of the clinical picture and typical findings on imaging. Some of these lesions are rare and have been described as case reports and series in the literature. This article aims to collate the clinical-radiologic findings of non-infectious and non-neoplastic causes of bone sclerosis with relevant imaging illustrations.

UNASSIGNED: This is a case report of a 16-year-old girl visiting MR Ambedkar Dental College and Hospital (Department of Pedodontics and Preventive Dentistry) for dental treatment.
UNASSIGNED: Osteopetrosis acroosteolytica or Toulouse-Lautrec syndrome or pyknodysostosis is a rare autosomal recessive bone dysplasia, characterized by osteosclerosis, and short stature. Montanari described a patient with an unusual variation of achondroplasia, which in retrospect was the first case of pyknodysostosis to be reported.1.
UNASSIGNED: A 16-year-old girl reported to the Department of Pediatric and Preventive Dentistry with a chief complaint of pain in the lower left back region of the jaw since past 2 weeks.
UNASSIGNED: Pyknodysostosis is a rare condition that is diagnosed basically on its clinical and radiographic features.
UNASSIGNED: It is important to recognize these features so that correct diagnosis can be made. This allows the treatment and prevention of future complications and ensures a better quality of life to the patient.
UNASSIGNED: Jawa A, Setty JV, Vijayshankar LV, et al. Pyknodysostosis: Report of a Rare Case and its Dental Management. Int J Clin Pediatr Dent 2020;13(2):192-195.

BACKGROUND: Pyknodysostosis is congenital osteosclerotic skeletal dysplasia of a rare entity. It is an autosomal recessive disease which presents with short stature and generalized osteosclerosis of skeleton as result of decreased bone turnover. Here, the authors report a case of pyknodysostosis who presented to our emergency room with a pathological fracture in the shaft of the femur for which operative intervention was carried out.
METHODS: A 30-year-old female presented to our emergency room with a history of trivial injury to right thigh region and was diagnosed as fracture in her right femur shaft region. After a detailed clinical, radiological, and blood investigations, the patient was taken up for operative modality of intervention in the form of plate osteosynthesis. As the medullary canal was narrow and bone was osteosclerotic, the option of closed intramedullary interlocking nailing was ruled out. Hence, we proceeded with open reduction and internal fixation with plate osteosynthesis using a board dynamic compression plate. Post-operative period was uneventful. Patient underwent non-weight bearing mobilization for 2 months. At 10-week post-operative follow-up, the patient presented with pain over surgical site and radiological examination showed no signs of union. The patient underwent additional plating augmented with bone grafting using grafts harvested from iliac crest and synthetic bone graft. The patient developed deep-seated infection immediate post-operative period for which she was treated with wound debridement, and appropriate intravenous antibiotics were given 2 weeks and orally for 4 weeks. At 6-month follow-up, the patient is able to carry her day-to-day activity with complete recovery and radiological signs of union. The patient had classical clinical features suggestive of pyknodysostosis. Patient has 2 siblings of same family (one brother and sister) with similar clinical and radiological features.
CONCLUSIONS: Recognition of these clinical and radiological signs is important to make the diagnosis of pyknodysostosis and prevent possible complications. Additional care must be taken in treating these patients.

Pyknodysostosis is a rare autosomal recessive skeletal dysplasia characterized by short stature, deformity of the skull, osteosclerosis, hypoplasia of the clavicle, and bone fragility. Radiographs show increased bone density, osteosclerosis, and acroosteolysis of the terminal phalanges. The pycnodysostosis gene is located on chromosome 1q21 and encodes an enzyme called Cathepsin K. Cathepsin K is a cysteine protease lysosomal protein associated with the degradation of bone and cartilage. In the current study, the authors described the clinical, radiological and molecular features of a group of six Mexican patients, including two familial and two sporadic cases, with Pyknodysostosis. One of the patients presented hypoacusia, an unusual finding in this disease.

Pyknodysostosis is a rare autosomal recessive disorder characterized by the post natal onset of short limbs, short stature, and generalized hyperostosis along with acro-osteolysis with sclerosis of the terminal phalanges, a feature that is considered essentially pathognomonic. Other features include persistence of fontanelles, delayed closure of sutures, wormian bones, absence of frontal sinuses, and obtuse mandibular gonial angle with relative mandibular prognathism. We report a case of 17-year-old girl who presented with a chief complaint of retention of deciduous teeth. General physical examination demonstrated short stature, frontal and parietal bossing, depressed nasal bridge, beaked nose, hypoplastic midface, wrinkled skin over the finger tips, and nail abnormalities. Radiographs showed multiple impacted permanent and supernumerary teeth, hypoplastic paranasal sinuses with acro-osteolysis of terminal phalanges, and open fontanelles, and sutures along with wormian bones in the lambdoidal region.